Final answer:
Odin regulated day and night using his ravens Huginn and Muninn, who would gather information about the events during the day and night and report back to him.
Step-by-step explanation:
Odin, a major figure in Norse mythology, regulated day and night by using his two ravens, named Huginn and Muninn. During the daytime, Odin would send Huginn to fly across the world and gather information about what was happening. Huginn would then return to Odin and communicate the news and events of the day. During the nighttime, Odin would send Muninn to fly across the world and observe what was happening in the darkness. Muninn would then return to Odin and report back about the activities of the night.